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3 years ago

A chemical change always involves a change to the --- of matter

Chemistry

1 answer:

faltersainse [42]3 years ago

3 0

Chemical composition.

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A chemical reaction takes place inside a flask submerged in a water bath. The water bath contains 6.50kg of water at 24.2°C. Dur

sukhopar [10]

Answer:

27.4°C

Explanation:

Using the equation:

Q = m*C*T

<em>Where Q is heat added,</em>

<em>m the mass of water</em>

<em>C specific heat of water (4.18J/g°C)</em>

<em>And T the increase in temperature</em>

We can solve for the increase in temperature and thus, the final temperature of water:

Q = 88200J; m = 6500g:

88200J = 6500g*4.18J/g°C*T

3.2°C = T = increase in temperature

Final temperature is:

24.2°C + 3.2°C =

5 0

3 years ago

How many valence electrons do nitrogen atoms have

julsineya [31]

Five valence electrons for one nitrogen and 10 valence electrons for two nitrogens

4 0

4 years ago

A civil engineering student is considering buying an electric car. However, the conscious student wants to make sure her carbon

svetlana [45]

Answer:

$\text{An gasoline-powered vehicle has }\\\boxed{\text{five times the carbon footprint}}\text{ of an electric vehicle.}$

Explanation:

1. Miles travelled in an average month

$\text{Miles} = \text{1 mo} \times \dfrac{\text{52 wk}}{\text{12 mo}} \times \dfrac{\text{5 da}}{\text{1 wk}} \times \dfrac{\text{16 mi}}{\text{1 da}} = \text{347 mi}$

2. Using a gasoline powered vehicle

(a) Moles of heptane used

$n = \text{347 mi} \times \dfrac{\text{1 gal}}{\text{36.5 mi}}\times \dfrac{\text{3.785 L}}{\text{1 gal}} \times \dfrac{\text{679.5 g}}{\text{1L}} \times \dfrac{ \text{1 mol}}{\text{100.20 g}}= \text{244 mol}$

(b) Equation for combustion

C₇H₁₆ + O₂ ⟶ 7CO₂ + 8H₂O

(c) Moles of CO₂ formed

$n = \text{244 mol heptane} \times \dfrac{\text{7 mol CO$_{2}$}}{\text{1 mol heptane}} = \text{1710 mol CO$_{2}$}$

(d) Volume of CO₂ formed

At 20 °C and 1 atm, the molar volume of a gas is 24.0 L.

$V = \text{1710 mol } \times \dfrac{\text{24.0 L}}{\text{1 mol}} \times \dfrac{\text{1 gal}}{\text{3.785 L}} = \textbf{10 800 gal}$

3. Using an electric vehicle

(a) Theoretical energy used

$\text{Theor. Energy} = \text{347 mi} \times \dfrac{\text{1 kWh}}{\text{5.2 mi}} = \text{66.7 kWh theor.}$

(b) Actual energy used

The power station is only 85 % efficient.

$\text{Actual energy used} = \text{66.7 kWh theor.} \times \dfrac{\text{100 kWh actual}}{\text{ 85 kWh theor.}}\times \dfrac{\text{3600 kJ}}{\text{1 kWh}}\\\\ = 2.82\times 10^{5} \text{ kJ}\$

(c) Combustion of CH₄

CH₄ + 2O₂ ⟶ CO₂ +2 H₂O

(d) Equivalent volume of CO₂

The heat of combustion of methane is -802.3 kJ·mol⁻¹

$V= 2.82\times 10^{5}\text{ kJ} \times \dfrac{\text{1 mol methane}}{\text{802.3 kJ}} \times \dfrac{\text{1 mol CO$_{2}$} }{\text{1 mol methane}} \times \dfrac{ \text{24.0 L}}{ \text{1 mol CO$_{2}$}}\\\\ \times \dfrac{\text{1 gal}}{\text{3.875 L}} = \textbf{2180 gal}$

4. Comparison

$\dfrac{V_{\text{gasoline}}}{V_{\text{electric}}} = \dfrac{10800}{2180} = 5.0\\\\ \text{An gasoline-powered vehicle has }\\ \boxed{\textbf{ five times the carbon footprint}}\text{ of an electric vehicle.}$

6 0

3 years ago

what is the oxidation state of each element in coh2? c o h what is the oxidation state of each element in febr3? fe br

fgiga [73]

The oxidation state of the elements in the compounds are:

CoH₂:

Co = +2
H = -1

FeBr₃:

Fe = +3
Br = -1

<h3>What is the oxidation states of the elements in the given compounds?</h3>

The oxidation states of the elements in each of the given compounds is determined as follows:

Cobalt dihydride, CoH₂

Co = +2

H = -1

Iron (iii) bromide, FeBr₃

Fe = +3

Br = -1

In conclusion, the oxidation state of the elements are charges they have in the compound.

Learn more about oxidation state at: brainly.com/question/27239694

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8 0

2 years ago

How many moles of KF are present in 46.5 grams of KF

irinina [24]

Explanation:

here's the answer to your question

4 0

3 years ago

Read 2 more answers